High harmonic generation (HHG) is a process that occurs when an intense laser interacts with a material and generates new frequencies of light. HHG has many practical applications, namely as a spectroscopy technique and source for high frequency light and attosecond pulses. While HHG has been done extensively in gases, HHG in solids is a relatively new field. Solids are appealing as an HHG medium as they require much simpler equipment and are subsequently much more compact, and thus may have a variety of applications previously inaccessible to gas-phase HHG. However, the generation mechanism of HHG in solids has not been fully characterized yet, as the processes behind HHG in gases and solids are not synonymous. Here, we study the influence of polarization, symmetry, and setup geometry on HHG in solids. We study the propagation effects in a transmission geometry setup and use Jones calculus to counteract the polarization change from propagation. We compare these results to a reflection geometry setup, which naturally does not have propagation effects, to determine the validity of the polarization correction technique. We also look at the electric field symmetry dependence on HHG through the manipulation of the laser electric field with a two-color interferometer. The impact of symmetry dependence and propagation effects both contribute to a better understanding of the HHG process in solids.
Bachelor of Science (B.S.)
College of Sciences
Crites, Erin L., "Polarization Dependence of High Order Harmonic Generation from Solids in Reflection and Transmission Geometries" (2020). Honors Undergraduate Theses. 693.